public void ConfigurationManager_WhenCreated_PopulatesConfigItemListFromFile() { // Arrange var configItems = new List <IConfigItem>() { new ConfigItem("key1", "value1"), new ConfigItem("key2", "value2"), new ConfigItem("key3", "value3"), }; _memoryCacheService.GetCount().Returns(0); _fileManager.ReadAllEntriesFromFile().Returns(configItems); // Act _configurationService = new ConfigurationService(_fileManager, _memoryCacheService); // Assert _memoryCacheService.Received(1).Add(configItems[0]); _memoryCacheService.Received(1).Add(configItems[1]); _memoryCacheService.Received(1).Add(configItems[2]); }